Rapid prototyping includes a group of technologies that create three-dimensional objects by the successive formation of solid layers from a fluid-like material adjacent to previously formed solid layers of material according to cross-sectional data representing successive slices of the three-dimensional object.
In one type of rapid prototyping, called stereolithography, a liquid material is selectively solidified by exposing it to actinic radiation. The liquid material is typically a photopolymerizable material. The actinic radiation is typically visible or ultraviolet electromagnetic radiation. The radiation can be produced using a laser, though other sources of radiation are possible, such as arc lamps or resistive lamps. Selective exposure may occur by scanning a beam, or by controlling a flood exposure by use of a light valve that selectively transmits or reflects the radiation. After an object has been formed by stereolithography, it can be heat cured. Liquid-based stereolithography is discussed, for example, in U.S. Pat. No. 6,406,658, assigned to 3-D Systems, which is incorporated by reference in its entirety. Examples of stereolithography systems include the SLA 5000 and SLA 7000 models which are sold by 3D Systems, Inc (Valencia, Calif.).
A second type of rapid prototyping is known as selective laser sintering (SLS). SLS is based on the selective solidification of layers of a powdered material by exposing the layers to infrared electromagnetic radiation to sinter or fuse the powder particles. SLS is described, for example, in U.S. Pat. No. 4,863,538, which is incorporated by reference in its entirety.
A third type of rapid prototyping is known as three dimensional printing (3DP). 3DP is based on the selective solidification of layers of a powdered material by the selective deposition (e.g., from an ink-jet printer) of a binder thereon. 3DP is described in U.S. Pat. No. 5,204,055, which is incorporated by reference in its entirety.